In a three-phase synchronous motor using permanent magnets, generally, in a motor in which stator windings are wound intensively around teeth, the ratio between the number of magnetic poles of permanent magnets to be used in a rotor and the number of slots (=the number of teeth) of a stator is often 2:3. On the other hand, there is known a synchronous motor using a combination of the number of magnetic poles of permanent magnets and the number of slots that can cause the magnetic flux generated by the permanent magnets to interlink stator windings more effectively (for example, Patent Literatures 1 and 2).
Furthermore, as a technique for causing the magnetic flux generated by permanent magnets of a rotor to interlink stator windings more effectively, there is known a technique in which the arrangement of the teeth around which the stator windings are wound is made non-uniform according to the combination of the number of magnetic poles and the number of slots without making the arrangement uniform (for example, Patent Literatures 3 to 5).